Balance in essential tremor during tandem gait: is the first mis-step an important finding?

Essential tremor (ET) is the most commonly diagnosed movement disorder. ET may cause substantial loss of motor skills and balance with advanced age. We compared abnormalities in tandem gait with daily activity and Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) scores in 90 ET patients. All patients performed a 15-step tandem three times. The mean of first mis-steps was accepted as the tandem index (TI). The mean age was 61.4 ± 17 years; the mean duration of tremor was 6.7 ± 4 years; and there were 36 men and 54 women. There was no significant difference for age or sex between patients and controls. Head (24.6%), jaw (5.5%), voice (11%), and tongue tremors (1.5%) were identified in ET patients. Rest (2.5%), postural (95%), and kinetic tremors (54%) were detected in the upper extremities. Postural tremor was found in the lower extremities of 5%. The mean TI was 8.3 ± 4 (median, 8) in ET patients, and 10.6 ± 3.9 (median, 10) in controls (p=0.04). Correlation analysis of TI and FTMTRS scores showed tandem gait was significantly correlated with age, total tremor score, postural and kinetic extremity tremor, writing, drawing, pouring, feeding, and working scores. Linear regression showed a significant effect of age and FTMTRS score on TI. The decrease in balance control is apparent with advancing age. Balance disorders were more pronounced in ET patients. Although first mis-step in tandem gait is not as detailed as dynamic balance tests, it can be a simple method for detecting balance disorders.